Just thought I'd pass along this tip. I checked my Activity Monitor for the first time yesterday, and found that some of the Widgets I had installed were real CPU hogs. Most of the Widgets used no CPU time when the Dashboard was not activated, but three of them were combining to use 35% of the CPU! In the background, without even being used.

I took those Widgets off the Dashboard, and my whole Mac Mini got snappier, I'm getting fewer spinning beachballs, and Photoshop has stopped crashing. If I want to use those Widgets, I'll just activate them and then close them afterwards.